Thermostatic controlling device



May 28,1935- l w. s. THoMAs 2,003,060

THERMOSTATIC CONTROLLING DEVICE Filed April 2, i954 2 Sheets-Sheet 2 Patented May 28, 1935 4UNfITED STATES 2,003,060 THERMQSTATIC 'CONTROLLING DEVICE William S. Thomas, Montoursville, Pa., assignor of one-half :.ville, Pa.

to Ernest L. Heckert, Montours-V applicati@ April z, ,ianserial No. 718,711

11 claims. (or. 236-32) or other element. Y

, One of the objects of the inventionl is tofprovide an .improved thermostatic` controlling deviceof this general rcharacter which is simple in structure, automatic and eilicient Yin operation, and entirely dependable from. asafety stand-1. y

' `this type with novel means for replenishing the point over long periods of service. j Y

Another object is to provide-a thermostat of novel construction that will be capable of repeated automatic voperation during .long service upon relatively small differentials intemperature without varying from desired limits ofaccuracy.

In known vthermostats of the gaseouspressue type, wherein a certain quantity of gas is initial. ly placedv in the expansion chamber and the chamber'is then sealed up, it has beenffound that after a period of use and repeated increases and decreases in the gas pressure inaccordance with temperature variations the pressure of the v gas'does not reach the same point at anyfgiven temperature as it did when the expansion chamber was rst lled. This defect in the operation of devices hitherto known and used by the prac'- tical art, which may bedue either to leakage that cannot be entirely prevented or to some'change in the composition of the gas itself, introduces a serious Vinaccuracy into the functioning of such devices vand isrthe basis of many complaints by users.-

of appliances embodying this type of thermostat.

Although thermostats operated by the expansion and contraction of a metallic medium have beendesigned and usedto eliminate the diicultieswith and objections to these gaseous thermostats of .the lprior art, it has been found that thermostats of the metallic `type are not nearly' so effective, and do not operate on as close tolerances, as 'those of the gaseous type. Itis obvious.

that where a solidmetal rod is usedras .an expanding mediumit cannot react as quickly as a for, their dissipation. `For example, where heavy withdrawals of water are made, such asin shower perature drop can be very great beforeK the solid Y metalyexpansion medium reacts to a, point of QUI whchwill unctioneiciently and accurately upon.

baths, laundry tubs, and in other ways, the tem.

small temperature variations over long periodsV ofY time without breakdown. Y f l It is therefore another-object. of the present` invention toprovide a novel form of` thermostat ofthe gaseous pressure type whichl isV charac? terized by the inclusion of means for insuring that the gaseous medium utilized always attains sub-- stantiallythesame pressure each'time that .the temperature is raised or lowered to any particular point. y Y 'Y rA further object is to provide a thermostat oft supply of the operatingV gaseous medium either automatically Aeach time the pressure thereof reaches, a predetermined point Vor the willoi the operator.

These andV other objects will appear more fully from a consideration ofthe detailed description ofthe invention which follows. Although `three different'emhodiments of the invention are described and illustrated in the accompanying drawings, it isto be expressly'understood that these drawings are for purposes of illustration only and are not to be construed as defining the scope of the invention, reference being had forthe latter purpose to the appended claims.

In the drawings, wherein like reference numerals indicate like parts throughout the several views:

- Fig. 1 isa sectional View of a thermostatically operated: valve assemblyfor a gas water heater' embodying one form of the present invention wherein thesupplyof expansible gaseous medium is automatically replenished each time that the pressure thereof falls to a predetermined point;

- Fig. 2 is a similar View of a portionof another embodiment". of the invention, also adapted for use in connection with a gas water heater, whereinthe replenish-ment of the supply of expansible gaseous medium. may be. eiectedmanually atj the will of the operator; and

Figs. 3 and 4 are plan and elevation views, rea spectively, with certain parts shown in section, of still another embodiment of the invention asv applied tothe cooling system of an automobile engine. v

Referring'rst to Fig. 1, there is showntherein a thermostatically controlled valve'assembly embodyingthe present invention associated with a. gas water heater, Vthe latter being of any'desired'. 50. construction .and only so much of the tank there: of. being shown inthe drawings as is necessary to illustrate the operation of the invention. In the embodiment showin the thermostat utilizes Vas its. expansible operating medium a quantity` of 545- l11A-'liliNT OFFICES manually at -1517 20 j and dependable operation of the heater, particularly by reason of Vthe. fact that the pressure of the gas in the expansion chamber which controls the opening and closing of the valve in the;

gas supply line always attains the same pressure each time that the temperature of the'wateriin.

the -tank reaches any given temperature. As one important advantage of'suchv a construction, it may be pointed out that by insuring the `closure of the` valve in the gas supplyline every time that the temperature of the water reaches a predetermined point, there is no possibility of overheating the water and consequent scald-` ing of the user should excessively heated water` be inadvertently withdrawnrfrom the tank and*V used, as in a shower bath.

' In the form shown, the valve assembly of the present invention comprisesgenerally an expansion or heating chamber 3, a pair of diaphragm encasing members 4.and 5, member5 preferably being formed integral with an outwardly Yprojecting cooling spacer member 6, and a valve casing member l. Diaphragm encasing member 4 is preferably provided with an inwardly extending, externally threaded boss' which is adapted Y embodiment illustrated, pressure chamber I3' is substantiallyV cylindrical in shape, whereas they to be threaded into the side of water heater tank 9, while the inner end. of said bossisrprovided with an enlarged recess in which is sealed in any suitable manner the open end of expansion or heating chamber 3, the latter preferablycomprising a tube of relatively large capacity formed.

of highly heat conductive material, such as hard drawn copper tubing, and projecting well within the interior of water tank 9 so as to be capable of readily absorbing heat from the surrounding water. Y y

7 Encasing members VV4 and 5 are provided-with complementary circumferential flanges whichareadapted to be secured to one another in any desired mannenas by bolts or screws I0, andbetweenl which is clamped the periphery. of a sensitive flexible diaphragm Il. It has been found that a diaphragmof German silver approximately ve inches in diameter and having a thickness of aboutk four thousandths of an inch is well suited for an installation of the character disclosed. f It will be understood that the joint between the flanges of diaphragm encasing members 4 and 5 is made as nearly air and gas-tight as possible by the use of 'suitable gaskets or other sealing means. Y

The faces of members 4 and 5 adjacent diaphragm II are recessed to provide suitable pressure chambers I2 and I3 on either side of the latterpressu re chamber I2 communicating with theinterior of expansion chamber`3 through a vsuitable passageway I4 extending axially through member 4, lwhile chamber I3 is connected to the valve chamber within valve casing member 'i' through another passageway I5 extending axiallyl through cooling spacer member B f In the central portion ofY chamberA `I2 ismore deeply recessed than the outer portion. With'this conbroken lines) will cause a flattening of the. outer portion of the periphery of said diaphragm against the wall of pressure chamber I2, as shown in Fig. l, and thereby decreasethe effective area of the diaphragm that is exposed to the fluid pressure within said chamber and expansion chamber 3. This construction is particularly useful in installations where it is desired that the gas valve be of. the snap acting type, although itwill be understood that the invention in its other aspects is equally useful with valves ofl the throttling type.

Y' The outer end of cooling spacer member 6 is also provided with an enlarged flange to which valve casing member 'Iris secured, as by screws I6, the joint between said members being rendered as nearly air and gas-tight as possible by the use of a'suitable gasket Il'. The space enclosed between' members 6 and 'I comprises a yvalve chamber I8 which is adapted to house a Asuitable valve for controlling the flow of gas to the burner of the water heater. In the embodiment shown, fuel vgas may be supplied at ordinary line pressure through a pipe I9 and inlet 20 to pressure chamber I3, the gas then passingV from chamber I3V through passageway I5 to valve chamber I8 whence it leaves through a suitable outlet' 2I and is conducted by a pipe 22 to the burner of the water heater. lThe passage of the gas from Valve chamber VI8 to outlet 2| is controlled by a Valve 23 of any desired construction having an adjustable valve seat 24 which is threaded into the wall of casing member 1 and is vprovided with suitable passageways communicating with botli'valve chamber I8 and outlet 2 I. By providing a threaded engagement between valve seat 24 and casing 1, the point at which valve 23 opens and closes communication between Valve chamber I8 and outlet 2| may be accurately adjusted.

The movements of valve 23 are adapted to conform to the movements of flexible diaphragm I'I,.the position of the latter in turn depending upon the variations in pressure exerted thereagainst, as will be later described. In order to provide an operative connection between diaphragm II andfvalve 23, the valve assembly illustrated includes a valve actuating rod 25 which extends through passageway I5 and engages at its opposite ends the 4center of diaphragm Il and the back of valvey23. If desired, rod 25 may be secured to diaphragm I I in any suitable manner. Valve actuating rod 25 is preferably of a different cross section than passageway I5 so that the spaces between the outer surface of the rod and the inner wall of the passageway may act as a restricted passageway through which gas may pass from pressure chamber I3 to Valve charnber I8.Y For example, if passageway I5 is circular in cross section it'has been found that a triangular valve actuating rod 25 is kwell suited for the'purposes of the present invention.

Valve 23 may be supported in its proper position adjacent valve seat 24, and in position to be engaged by one end of actuating rod 25, by a suitable lever 26, one end of which is secured to the back of valve 23 and the other end suitably fulcrumed in a forked lug 21 projecting inwardly from the wall of casingmember 1. In order that valve 23 shall follow the movements of diaphragm II in both directions, and also for the purpose of accurately adjusting the valve mechanism so that it will open and close under predetermined conditions, means' are also provided for yieldingly urging valve 23 to Athe right, as viewed inFig. Asv shown, casing member fl is 2;.,O35O0N' Y -vided fori-indicating uthe temperature `ofi-"the prevented-with a boss 2s; the miler end if which is vinternally.threaded to receive an vaxiallyre'- cessed adjusting member 29. -Withn' the recess of said member 29 is housed a suitable spring'f-BIL the inner end of which exerts a pressure against aplunger3l slidably mounted in the' inner 'end ofmember 2S and engaging valve lever 26 at such a point as to tend to move valve`23 to the right, asI viewed in Fig. 1. The outer end of adjusting member 23'is provided withan enlargedk circular adjusting head or handle 32which isV preferably calibrated' interms of the water temperature j which it is desired to maintain withinf'tankfs, the setting at any particular position'being indie cated by an index Lmember 33 cari-led by casingVV member l.

Withthe construction Athus far described, .iti

will be obvious that the positionsV of diaphragm II and valve 23willldepend-uponY the fluid pres'- sure in pressure chamber I2, the gas pressure inV pressure chamber. I3 Vand valve chamber I 8, and the adjustable pressurevexerted by spring 30, the pressure inpressure chamber I2 in turn being dependentupo'n the quantity andifcharacter of the iluid medium within Vexpansion,chamber 3 and the c temperature .of the water in 'the y tank surrounding said chamber. In devices of this general Vcharacter hitherto known to the art, it

has been Vcustomaryr to yplace a quantity oir'exel pansible fluid medium in expansion chamber 3 when thefdevice is initially installed and to rely upon the efficiency of the sealing of the various elements toene another to prevent escape of said medium. However, it has been found that, either n because of leakage which cannot be entirely prevented or because of some unknownchange in the composition of the fluid medium itself, such devices cannot be depended upon to always operate at the same water temperatures after any substantial period of service. Y i 5 Means have therefore been provided by the present invention for insuring continued, automatic, accurate operation of the Vvthermostatic device, wl'iichy means -are'characterized by 'an automatic replenishment' of the supply of expansible uid'medium each time that the` pressure of that' medium reachesfa predetermined point'. In the particular embodiment illustrated,l

the expansible fluid medium utilized in expansion chamber 3 `andpressurechamber I2. is the same gas. as that which is supplied to the 'burner of vtde water heater, and meansrhave been V'provided for replenishing the supply of said gas within pressure chamber I2 and expansion chamber 3 each time that the pressure therewithin falls to a point just below the pressure ofthe gas in supply pipe I9. Y Y As shown, pipe I9 is provided lwith a suitable Tconnection 34 which receives one end of a bypassfconcluit or pipe 35, the other end of which is connected to pressurechamber I 2 througha pair of check valves 36 arranged in series and a passageway 3l `iormedvin'the Wall offencasing member Il. Check'valves 36 are `preferably of relatively light construction and, in order to insure their operationupon smalldifferentials in"` pressure, may be mounted with their axes horizontahinstead of vertical-'as' shown, so` asV to` eliminate as farras possible the gravitational effect of the valves themselves. Y Y Y For calibration and checking purposes, pressure` chamber'IZY may be providedwith a suitable'pressure gauge 38, while a similar gauge 139 may be connected to gas-'pipe v22. A'fthermometer 40 of any'suitablelconstruction mayj also be pro-l.

-on handle 32. Whenfu'sing-a pressure Vchamber I2 ofthe con'- water withintankl 9. Y

Inv order to prevent vany undue increase in the pressure of the gas vin vvalve chamberv I8 due to the conduction of heat from the water in tank 9' through"v the metallicwalls of members3;V 4, 5, "6 andV 1, which increase-lin pressure would'be ex-y erted' upon'the back of valvev23 and'oppose its opening, spacer member Ilmay be'provided with l 1.0. `In operation, the thermostatic controlling de- A ,Y

a pluralityfof cooling fins 4I.

vice ofthe lpresent invention functions as fol-r lows: Assuming that the'waterin tank 9 islcold,

as for example at a temperature of 40 as indicated on `Vthermometer 40, thepressure of the gas Within" expansion chamber 3 andf-prjessurc chamber I2-fwill*be relatively low and the line' pressureof the gas in pressure chamber I3 and valve chamber I8 plus the Y'pressure ofspring 30 exerted againstleve'r 2G `will be more thanV suffi-r `cient to rforce diaphragm II to the right, as

viewed-in Fig. 1, andto open valve 23, thereby permitting gasto passfrom' supply pipe nI9(A through pressure Achamber I3 restricted --passage-Y way I5 andY valve chamber I 3 'to outlet-'pipe22 whereby it -i`sfcarried"totheburner of the 'water heater. At the same time, sincethe gas, pressure f' within' pressure 'chamber I2 is lessth'an the line Y pressure which exists', in supply pipe I9 and chambers-l3v and I 8, check valvesSG'fare open so that communication isestablished between supply pipe `I 9 `and pressure ichamber' kI 2 Ithrough,

b'y-pass conduit 35j thereby.'l enabling expansion -V of the gas within expansion chamber 3 and pres# ysure chamber VI2 has been increased to the pointV where thegaseous pressure becomes' slightly greater than the line'pressure of the gas in supply pipe I 9,-check valves .36, are closed. .Con-

tinued heating of the water fin' tank y9 progres sively increases the gaseous pressure within expa-'nsio'n' 'chamber 3 and pressure chamberv I2,

and thatpressure is exerted against diaphragm Y II in opposition to the gas pressureV in chambers I3 and I8 and the pressure of "spring 30. When the. temperature ofthe water in the tank reaches the predeterminedV point at which the device hasV been calibrated, the gas pressure within chamber Y Y I2 becomes greater than the sum of the gas pres-l Vsure'in chambers I3 and I8 andthe pressure of springQSI), moves/diaphragm II t`o the left, and,` through valve actuating rod 25,V closes-valve 23,v thereby-cutting off the supply of gasto the burner of the waterk heater.4 -If vitrbe assumed that the water temperature at vwhich valve 23r is Vclosed that, with'a setting of spring 30 such as to per-l mit-closure of valve 23'just when-the tempera-A is regulating handle32 will beso calibrated.'l

tureindicated by thermometerilrrreaches 140,

index-33 will rcorrespond with areading of 140 struction'` shown in "Figi 1,7hig'h1y efcie'nts'nap'V action inthe closing of valve 23'is obtained since, as soon as the pressure in chamber. I2 becomes sufficientlyfhigh tostart movementof diaphragm I I tothe left` and' out 'of contact y.with thefouter posing pressure.

portionr ofthe'wall of chamber', the area' ofthe diaphragm exposed to the' pressure of the expansible gas is suddenly materiallyincreased and the total pressure acting to closethevalve becomes Vrelatively much greater than the op- The result isthat valve 23 is quickly and forcibly movedgto closed p osition.

VAs the V water within tank 9 cools, orjwhen some of the hot water Vis withdrawn andreplacedjoy cold water, the temperature and pressure of theA gas within expansion chamber 3 .and `pressure chamber; I2 also decrease. WhenV this gaseous pressure drops to the point where itis less than.A

the combined pressureof the gas i n chambers I3 and I B and the pressureexerted by spring 35, .the

diaphragm I I is again moved toj the right soas topermit valve23 to openandagain establish a vflow of gasto the burner of. the heater. Snap ati- A tion is also obtained upon opening of lvalve 23 in they following manner: vWhen Svalve 23 isV first cracked, there is a sudden rush of gas from valve chamber I Sinto pipe 22 downto the burner. Although this results in a momentary drop in pressurein valve chamber I8, the throttling effect ofj the burner and the elasticityof the gas in pipe 22.

causes aback pressure vto be quickly built up in valve chamber I 8 and pressureV chamber I3, which back pressure is exerted against diaphragm II and *forces it to the right with a snap. With the form of device illu-strated, it will be possible to so calibratethe device that a'decrease o f as little as from i to 10 in temperature of the water within tank 9 below ,the temperature set :on hand wheel 32x/vill be effectiveto Vcause an opening of valve dium ofthe thermostatic device, its operation is always based upon a relatively fresh" supply of gas 'at a known ybasic pressure with the result vthat the gaseous pressurewithin chambers-3 and I2 always reaches tlie'same point everytimethat the water within tank 9 reaches anygiven temperature, regardless of the length vof timethat thedevice has been in servicef .The embodiment of the invention illustratedin Fig. 2 of the drawings is similar in construction to that ofFig.V l withthe exception that thebyjvpasscmne'ction between gas supply pipe. I9 and,

pressure chamber I2- is omitted .and suitable means are substituted therefor wherebythe sup-V plyV of gaseousmedium within expansion cham- 'oer 3 and pressure chamber I2 mayY be; re,-

plenished manually.Y As shown, itis assumed that the gaseous medium utilized in expansion chamber.3 and'pressure' chamber I2 is air, the V.supply of which may be replenished at-thewillof ythe operator bya pump of any desired construction, such as a rubber bulb 42' having an inlet Vvalve I 43 and beingccnnected with pressure chamber I2 through a check valve -and .p assageway'l. With this construction, whenever the' pressure indicated'on gauge V38 variesfromfa predetermined relationship with the temperature indi cated by thermometer 45, a relationship which may be computed and supplied to the user of the device in the form of a table, additional .air mayA be pumped. into chamber I2,by bulb 42.unti1 the of the water inthe tank as indicated by ther-A Referring new' ,to Figs. 3 and 4, there is dis- 'closedtherein a portion of the cooling system of an automobile engine whichembodies a thermostatic device constructed in accordance with the present invention for'controlling the position of the radiator shutters, which position in turn governs the cooling effect of the radiator upon the water flowing therethrough. As shown, the upper portion of the automobile radiator 44 is provided with a suitable rearwardly extending tank 45 to whichis connected the hose 46 leading from the cooling jackets surrounding the engine cylinders and into which the vwarm water leaving the engine block is delivered. From tank 45, the warm water p asses into the tubes of the radiator honeycomb 4'I and, during its passage downwardly therethrough, is cooled by theair that is drawn through Athe honeycombby a fan 48 in the usual manner. In order to control the degree of cooling thus attained, the front of the radiator isprovided with a well known arrangement of 'adjustable shutters indicatedgenerally at49. l V

Ithas been customary to regulate the position of the radiator shutters either manually from the drivers position or automatically by means of thermostatic'devices well known to the art, but

in no prior system of which vapplicant is aware have thesel shutter control devices proven sumciently accurate and reliable to be entirely satisfactory duringpcontinued use' over long periods of service. However,V by the use of the thermostatic controlling'device of the present invention, the radiator shutters may be continuously and ac curately adjusted to such positions that the temperature of the water within the cooling system may always be maintained at or below a desired temperature. v Y

In the constructionrillustrated, an expansion tube or chamber 55, Vclosed at one end and having walls of relatively highly-heat conductive material,.is mounted within tank 45 in any suitable manner in Asuch position as to be'surrounded by the waterof the cooling system as it is delivered from the engine block through hoseconnection45.4 For. example, the open end'of chamber 5G may be suitably secured in a recess formed in the boss 5I of a casing member 52 and the latter secured to tank I5 in any desired manner, as by threaded engagement between boss 5I and the wall of said tank, as shown. lThe outer face of' member 52 is recessed to provide a pressure chamber 53 which communicates with the interior of expansion chamber 55 through a suitable passageway 54. Clamped between a flange vformed on member-,52 and a similar flange formed on a complementary casing'member 55 is the periphery of a exible ldiaphragm 56, one side of which forms a movable end wall for pressure chamber 53 and expansion chamber 50, while the other side is engaged by or has secured thereto one end of; a'push rod 51, the other endV of which extends outwardly ofv casing member 55 and is connected to one arm of a 'suitablelever 58 fulcrumed as at 59 in a lug 6G projecting from casing member55.

The other arm of lever 58 is connected through any suitable mechanism, such as the link and lever arrangement indicated generally at 6I, to the radiator shutters 49. f

The interiors of `expansion chamber 50 and pressure chamber 53 are filled with an expansibley fluid medium of` any preferred character, the pres-I sure of which. is exerted against diaphragm. 56. and tends to move rod Y5'lto the left, as viewedin, the. drawings, the connections between said rod and the radiator shutters Il@V being such that said movement to the` left increases the 4opening of said shutters, thereby increasing the cooling effect of the radiator.y Since theuwalls of expansion chamber`5ll are of highly heat conductive material, and since the volume of said chamber is relatively' large, variations in the temperature of the Water in tank are quickly manifested bychanges in the pressure ofy theruid medium said expansion chamberV and pressure chamber 53, which variationsV in pressure in turn varythe positions of diaphragm 56, rod 5l and shuttersA d6. In order to move rod 5'! and diaphragm 5,6 to the right and close shutters 49 when the fluid pres-- sure within chambers 50 and 53y falls, and in order to provide an accurate adjustment for the device,` the outerend of rodl5'l maythrust against the pressure of a suitable spring 62 housedv Within a recess formed in adjusting member 63, the free end of said spring being seated against a plunger G4 which in turn abuts the endof rod 51. Adjusting member 63 is externally threaded into a bracket 6.5 which may conveniently be carried by orformed integrally with casing member 55, the threaded engagement between member 63 and bracket 65 providing a ready adjustment for the pressureof spring -62 and :for calibration of the thermostatic device. Y

In order that the iluid within chambers 5i)l and 53 may always attain the same pressure (and thereby open the shutters 49 the same amount) Y each, time that the temperature of the waterin tank 45 reaches any given value, regardlessofv the length of timethat thedevice has been in service, suitable means are provided -for automatically replenishing the supply of'uid medium Within said chambers at certain intervals. In theembodiment illustrated, 'assuming that atmospheric air is. utilized-as the expansible iiuid medium, means are provided for automatically opening chambers 5G and 53 to the atmosphere each time that the pressure therevvithinV falls toy oir-slightly below atmospheric, thereby insuring continued accuratey operation ofthe device. vAs shown, this improved result is attained by the simple expedient of connecting. chambe1f53 to the atmosphere through a restricted passageway 66 formed in member 52 and a suitable check valve 61 of sensitive construction, the inlet nipple 68 of the latter being open to the atmosphere. Y With this-construction, each time that the pressure rof the air within chambers 5a and 53 dropstto. or slightly below atmospheric pressure, check valve 6T will open and the supply of air within said, chambers may be replenished from the atmosphere.

It is believed that the operation'of the device illustrated in Figs. 3 and 4 is apparent from, the preceding description of its construction and from the previous discussion ofthe devices of Figs. 1 and 2.. It will also be readily appreciated that the controlling device of Figs. 3V and 4 is Vequally well adaptable for uses other than operating the which the cooling water is led back to the engine 70 'blockfrom the radiator.'A

There is thus provided' bythe present invention a simply constructed thermostatic controlling de-4 vice of novel character that is capable of ueiiicient,

'automatic operation during long service without deviating from desired limits of accuracy. The

, chamber;

device is particularly adaptable for useas the controlling unitv of a gas water heater or an automobile vradiator installation, since the novel construction provided insures accurate and safe operation regardless of the length of time that the in the embodiment of Fig'. 1 the expansible fluid f medium used isv the same gas that is Vsupplied t0 the burner of the water heater, it will be apparent that any `other suitable fluid medium `may be utilizedand that pipe' 35 may be connected to any suitablesource of such medium instead of to the gas supply pipe,V as shown. Likewise, if it is desired to use air as the expansible actuating rne-A dium inthe embodiment of Fig. l, it is obvious that the desired results would be obtainedsimply byV leaving pipe 35 open to the atmosphere, asis shown in Fig. Y3. Similarly, the well known bulb pumping.y arrangement of Fig. 2 may be replaced by any other suitable means for performing 'the same function,and.may utilizev any desired uid medium instead of air, asshown, while. the embodimentof Figs. Sand 4,may secure replenis'hing `Iluid from any suitable source other thanfthe atmosphere, suchasa reservoirof .ether or other expansible medium connected to nipple 68 of check valveA 61.

It will also be clear to rthose skilled in the art that by placing the valveassembly of Figs.1 and 2 in proper relation ,to the diaphragm, the cycle of operation. can be reversed so that the expansion of fluid mediumwi'thin the `expansion chamberwill open a valve. instead offclosing'it thereby t valve casing member 'i made integral with memf ber 5, in which case valve chamber I8 and pres,- sure chamber i3 willbe combined into a single On vthe other hand, the gasfsupply pipe I9 may be led directly into valve chamber I8, with no connection to the space designated as mentof Figs. Seli. Furthermore, it isto be distinctly understood that the invention is not limited to use in connection 'with a gas water heater be utilized wherever a highly sensitivay accurate thermostatic controlling device is desired. ForY example, instead of controlling the opening and closing of a valve or a radiator shutter, the move- .ments of the flexible diaphragmare equally-well adapted for opening and closing an electric circuit of any desired character. f

Various other changes, which will now occur to" those skilled in the art, may be made inthe form,

details of'construction andarrangement of the parts without departing from the.. spirit of ,the invention. ReferenceV is therefore to. be had to ofthe invention.

l. In `a thermostatic controlling device, a movable diaphragm operatively connected to the element to be controlled, an expansion chamber communicating with one side of said diaphragm and-adapted to be heated by a medium the temperature of which varies in accordance with the position of the element being controlled, said expansion chamber containing a quantity of eXpansible. uid medium the pressure of which :varies with changes in the temperature of the medium by which the chamber is heated and tends to move said diaphragm in one direction, means for opposing theV pressure of said iiuid mediumA 2,017 said Yiiuid mediumeach time that the pressure of said mediumV within said chamber reaches predetermined point. Y Y 2. `In a thermostatic controlling device, a movable vdiaphragm operatively ,connected to the element tobe controlled, an expansion chamber communicatingwith one side of said diaphragm and; containing a quantity of expansible, fluid medium the pressureof which tends to move said diaphragm and controlled element in one direction, meansfor opposing the pressure of said uid medium against said diaphragm and tending to mov'eithe latter'and said element inthe opposite direction, and means for automatically replenish ing the supply of fluid medium in saidexpansion chamber wheneverthe pressure. of said' medium drops to a predetermined point. i j 3. In a thermostatically operated valve assembly, an expansion chamber havinga quantity of `expansible fluid therein, 'a movable diaphragm closing one end of said chamber, a valve, means operatively connectingsaid diaphragm and valve for moving the latter in response to changes in the pressure of the uid in said'expansion chamber, means for moving the diaphragm and valve ina direction opposite to that in which said elements are moved by the pressure of the uid in said expansion chamber, and meansforautomatically establishing communication between the interior of said expansion chamber and a source of said expansible fluid whenever the uid pressure within the expansion chamber reaches a predetermined point. l

4. In a thermostatically operated valve assembly for a gas water heater, an expansion chamber exposed to the temperatureof Vthe Water in the heater and containing a supply of expansible fluid medium, a movable diaphragm closing one end of said expansion chamber, a valve chamber, a gas inlet'to and a gas outlet from said valve chamber, a valve controling thepassage ofI` gas from saidinlet to said outlet, means operatively connecting said diaphragm and valve for moving the latter in response to changes in the pressure v of the fluid medium in said expansion chamber,

vmined point. Y

meansformoving the diaphragm and valve ina 'direction opposite to that in which said elements Vexpansible uid whenever the fluid pressure within the expansion chamber reaches a predeter-` 5. Ina thermostatically operated valve assembly for a gas water heater, an expansion chamber exposed to the temperature of the Water in the chamber, a valve chamber, a gas inlet to and aV gas outlet from said valve chamber, a Valve controlling the passage of gas from said inlet to said outlet, means operatively connecting said diaphragm and valve for moving the latter in response to changes in the pressure of the gas in said expansion chamber, means for moving the diaphragm and valve in a direction opposite Vto that in which said elements aremoved by the pressure of the gas in said expansion chamber, and means for. automatically establishingcommunication between the Vinterior of said expansion chamber and a source 4of the gas supplied to said valve chamber whenever the gaseous pressure' within the former reaches a predetermined point. Y l

6. In a thermostatically operated valve assembly fora gas water heater, air-expansion chamber exposed to the temperature of the water in the heater and containing a supply of gas, a movable diaphragm closing one end of saidv expansion chamber,l a valvev chamber, a gas `inlet to and a gas outlet fromY said valve chamber, a valve convmunication between said expansion chamber and said gas inlet whenever the pressure of the gas in said expansion chamber falls to a predetermined point. Y

'1.` A thermostatically operated valve assembly comprising an expansion chamber having a wall of highly heatconductive material and adapted to contain a quantityY of. expansible uid, a nexible diaphragm closing the end of said expansion chamber, aY valve chamber communicating with the opposite side of said diaphragm through an elongated, relatively restricted passageway,l a

' uid inlet Yto and a uid outlet from saidvalve chamber, a valve controlling the passage of' uid from said inlet to said outlet, means operatively connecting said diaphragm and valve whereby the latter may be moved in one direction by the pressure of the expansible uid in said expansion chamber, means including the pressure of the fluid supplied to said valve chamberv for moving the diaphragm and valve in the opposite direction, and means for cooling the material surrounding said restrictedv passageway, thereby preventing any increase in pressure of the iiuid in said valve chamber due to conduction of heat from said expansion chamber.

f 8. A thermostatically operated valve assembly comprising la exible diaphragm clamped at its periphery' between a ,pair of encasing members, each'of said members being recessed at its face vadjacent said diaphragm rto providejrpressure chambers on opposite sides of the latter, an expansion chamber communicating with one of said pressure chambers and adapted to contain a quantityof expansible-luid, a valve chamber communicating with the other of said pressure said valve chamber, a valve controlling com- 9. A thermostatically operated valve assemblyV comprising a iiexible diaphragm clamped at its periphery between a pair of encasing members, each of said members being recessed atitsface adjacent said diaphragm 'to provide pressure chambers on opposite sides of the latter, an ex-v pansion chamber communicating With one of said pressure chambers and adapted to contain a quantity of expansible fluid, a valve chamber communicating with the `other of said pressure v chambers through an elongated, restricted passageway, a uid inlet to said last named pressure chamber, a fluid outlet from said valve chamber, a valve controlling communication between said fluid inlet and outlet, means operatively connecting said Valve and diaphragm for movement together in one direction in response to the fluid pressure in the pressure chamber communicating with said expansion chamber, means including the pressure of the fluid in the pressure chamber communicating with said valve chamber for urging said valve and diaphragm in the opposite direction, means for cooling the material -surrounding said restricted passageway to prevent the transmission of` heatvfrom said expansion chamber through said encasing members to the uid in said valve chamber, and means for automatically establishing communication between said two pressure chambers whenever the iiuid pressures therein become substantially equal. Y Y,

10. Ina coolingu system including a radiator and means governing the cooling effect of said radiator, the combination of an expansion chamber having a wall of yhighly heat conductive material exposed to the temperature of the medium to be cooled in said radiator, said expansion chamber containing a quantity of expansible uid, a Y

iiexible diaphragm closing one end' of said eX- pansion chamber, means'operatively Aconnecting said diaphragm and said governing means for movement together in one direction in response to the iiruid pressure in said expansion Vchamber, -means for urging said diaphragm and governing means in the opposite direction, andv means for automatically repleriishingV the supply V'of expan sible iiuid Within said expansion chamberwhenever the iiuid pressure therewithin reaches a predeterminedpoint.

1l. In-.a cooling system including a radiator andrmeans governing thecooling eiectof said radiator, the combination of an expansion chamber having a Wall of highly heat conductivemav terial exposed to the temperature of the medium chamber, means for operatively connectingV said diaphragm` and said governing means' for move-.

ment together in one direction in response tothe pressure of the air in saidv expansion chamber,

means for urging saiddiaphragm and governing means in the opposite direction, and a check valve connecting said expansion chamber with the atmosphere for replenishing the supply of air therewithin whenever the pressurey thereof is reduced. below atmospheric.V Y

' wILLiAM s. THOMAS; 

